People seem to be having good luck with most of the cam selections currently on the market, but I often hear "there's no FI specific set of cams out there right now." What's the hold up? What attributes would most beneficial to an FI car? What are the effects of using different intake/exhaust cams together?

 

most street f/i cams tend to has less overlap of the intake and exhaust valves (the time your exhaust valve is still open, and the time your intake valve starts to open) it stimulates the flow in an n/a application, but with f/i, you will pass some of the charge out of the exhaust valve. overlap will effect the lobe centerline too. a lower # on the lobe centerline is better. at the same time, with a lower lobe centerline, you have trouble getting alot of duration. high lift is the main way to help a turbo or s/c car to breath better. also the exhaust pressure in the exhaust manifold to spin the turbo is higher, thus making the over lap benefits, not a benefit on a turbo motor. an s/c motor will not have the high exhaust back pressure at that point, but will still not like the overlap for the previous mentioned reason.
now to have a cam with more lift, you will have to get better valve springs to help control the valve at high rpm. it doesn't sound like valve springs have come to far at all on these motors because the allowable spring height does not give a manuifacturer much room to work with. i have a feeling machining the spring seats down is what it will take to start putting alot nastier cams in the vq35. it isn't a hard machining thing to do, but no cams out there yet to require it.
simply put, lol. thats my opinion on the subject.

 

u know ur shat. lol.

 

lol, glad i'm fooling someone.

 

Well i knew all the overlap stuff about NA.. thats why NA harleys and wild cammed muscle cars go pop pop pop..its the exhaust gap inbetween from either cylinder bank. I didnt know any of that about the FI stuff.

 

just get some custom....there are a few guys round here with CGC.......so just ask them

 

During a lengthy discussion with Jim Wolf he pointed out that their S1 cams are designed to work well with superchargers and their S2 cams are specifically designed for turbochargers--reduced reversion etc.


DaveO

 

hmm intresting... specs on the S2 cams???